Anritsu 69337A Signal Generator

The Anritsu 69337A Signal Generator has a Frequency Modulation (FM) for the oscillator tuned YIG. The RF output is accomplished by including interior modulation signals in the FM control path of the YIG loop. The external modulation signal originates from the front board or FM IN input on the back board. The intern modulation signal originates from the A8 function generator PRINTED CIRCUIT CARD. The circuits of the A11 FM PCB modify the modulation signal for the selected FM sensibility, then add it to the FM control path in the YIG loop. From there, the recurrence modulates the RF output signal controlling the FM of the tuner oscillator YIG (fine tuning) current coil.

The 69337A CPU programs the coarse-loop oscillator's output recurrence so one of its harmonics will be between 30 to 40 MHz of the desired YIG-tuned oscillator's output recurrence. The YIG Loop phase detector compares the YIG IF signal to the 30 to 40 MHz recurrence reference signal from the Fine Loop. If there is a distinction, the YIG phase detector calibrates the YIG-tuned oscillator (through the FM hardware and the FM coil driver) to wipe out any recurrence contrast between the two signals.

Phase locking the Anritsu 69337A Signal Generator’s output recurrence over an expansive recurrence range is accomplished by programming the coarse-loop oscillator's output to various frequencies that have harmonics near the desired working frequencies. Correct recurrence tuning for each desired working recurrence is accomplished by programming the fine-loop oscillator. For each situation, the YIG-loop oscillator is first tuned by means of the principle tuning loop to the surmised working recurrence.